At the risk of completely derailing the discussion, sometimes the UI simply just needs to be learned. People who are unfamiliar with elevators would have no idea how to use one.. there's no instructions anywhere, just a panel with numbers. If you aren't familiar with those bathroom faucets that turn on when you put your hands under them, you'll spend a few minutes just staring at it looking for a knob. Eventually, it catches on.

You are right that there's an initial curve, though, and I don't know how to deal with that other than just through the painful experience you described.

Of the top of my head: start off with big up/down buttons. Then show a list of floors. Some people won't notice the second press required, but it's a start. I was confused by those things the first time too.